Several days ago my friend Rifty asked me to explain some mechanics of league of legends. So instead of explaining through chat, I decided to explain everything in article form. I got a positive feedback from my friends so I decided to post it on redit.

How to not suck at lol
What is your role ? In lol we have 5 basics roles. Mid, Solo top, AD carries, Jungle and Support. Every champ has his own role and is strong in different ways. On low Elo level it always cracks me up how ad carry flame support because he´s weak in fights etc..
Ideal team composition is to have AP caster, Tank, Assasin, AD ranged, Support. This is not strict, they are lots of people who play tank as a support. Or AP caster as a tank etc..
I will be explaining the basics mechanic in each column. Don't just read individual role because that's the role you are interested in. Learn all roles. This will give you advantage to fight against enemy role and helps you to understand the soul of the game :D

Roles
Mid - Role of the mid is securing mid lane. This lane is important because it´s very easy to farm and mid laners are usually 1-2 levels ahead. On mid we usually take AP based champion.
-Why AP ? Because AP champions are usually main DMG dealers in early to mid game. Thanks to theyr ability damage and great ap ratios. If you pick Tank or AD carry against another AP caster 90% times AP caster wins. There are some exceptions I will discuss later on.
-What are important things to remember while playing mid ?
Last hit, I can´t stress this enough LAST HIT. This is important to all lanes not just mid. By last hitting you won't loose farm to your opponent who burst all minions as soon as he sees them, but more often than note you will be ahead in creep count. By last hitting you don't push your lane and you face less danger from enemy jungle and enemy mid.
If you push your lane, don´t be aggressive. Wait back and occasionally last hit, or wait in the bush, but don't attack recklessly. By being aggressive you probably lose more HP and MANA. It is bad to have pushed lane, because it gives a clear sign for enemy jungle or laners to gank, and without MANA or HP it is almost impossible to escape.

Example of early game: I play on mid mostly Le Blanc. I usually start with amplifying to me, because I have mana regen from runes, and some additional Magic resists. In first couple of minutes I secure blue or red for our jungler.

-Why ? One of enemy tactic is to deny blue or red for our jungle. This way our jungler isn´t so strong in jungle and his ganks become weak or slow. If enemy indeed shows up I retreat to the next safe position and rally our team, this way we can at least defend or deny our blue.

Then I immediately rush to my lane and I start to farm. (Loosing 1 or 2 creeps aren't that much of a deal. Better than loosing our golem and jungle) I only last hits minions and ignoring enemy champ.

-Why ? Isn´t it better to harass him to leave my lane ?
Yes in some situation it is, but not as Le Blanc. She has big dmg on her abilities, but she is squishier than she looks. Another reason is to get the first kill once she reaches 5 - 6 level. She gets insane damage once she reaches this level. And by harassing enemy you force him to retreat early and buy some additionall items. When he returns you will be outmatched by his superior upgrades and your hopes for the early kill are gone.
I wait till level 6, harassing little in order to deplete his potions. When I reach level 6 I immediately jump to him emptying all my abilities in order W-Q-R-E and ignite. And killing him.
1, I kill few low HP creeps and recall to base. If I have low HP I retreat behind second tower. Luckily shaking enemy jungler.
2, If I have enough MANA and HP, I retreat behind my tower, or out of the vision of creeps and help to gank other lanes. Hopefully securing other lanes or scoring a kills in the process.
I buy a soul stealer and several potions and return to my lane.
Remember : Don't be so aggressive early on. Ward your lane if you can. Target, supports, AP casters. Ganks if you have nothing to do.
SOLO TOP
His objective is to get farm from top lane and secure area under him. On solo top we usually pick tank, or AD based champion with high sustain.

Why ? – In order to have a good farm we need high sustain. Because top lane is longer and further away than mid. We can have sustain by having a high HP and MANA regeneration or by being a tank and taking no to little dmg from enemy.
As I say before farm only by LAST HITTING. Solo top is most vulnerable to ganks and tower dive. If I somehow manage to push my lane I WARD. If I don't have ward, I recall and then ward. By warding you have a vision against enemy gank and this gives you enough time to hide in bush and run away.
Note – Even if you have vision, some junglers are really fast, and you might not react in time. Against invisible junglers we buy vision wards.
If you are beginner, try not to over-extend. Not to be aggressive and not to try to kill him. Harras only if you are sure there is no enemy jungle, and he will not deal you more dmg than you to him.

An example of early game : My favorite champion at solo top is Irelia. Irelia is really dependant on items. So we buy items who produce gold per 10 sec. I start with full defense masteries and rest in the attack. My start items are regrowth pendant and mana potion. In first couple of minutes I secure blue for our jungle by standing on near to exit from our jungle near blue and guarding it this way. After our mid pull blue or red for our jungle I am retreating to my lane and start to farm with LAST HITS :D. (It's getting old, I know). I´m caring for an enemy jungle first couple of seconds.
-Early gank top is the usual tactic for champs like Evelyn or Lee sin etc..
We both last hit for a time but his last hitting is better and my minions are pushing the lane. When my minions are almost at his tower I recall, buy ward and return to my lane. I return when his minions are in the center of the lane. I ward my bush on the bottom of my lane and return to farming. Near level 3-4 I see the enemy jungle on my minimap. I signall our mid to help me and I bait enemy jungle. He takes the bait he jumps on me, exhausting me in the process. I flash away and escape while Exhaust is on me. When exhaust vanishes I jump on him by Q with W active. Enemy solo top and jungle are killing me fast but our AP caster jumps on them fast and killing enemy jungle. Enemy Solo top escapes. I recall and buy Philosopher stone, hearth of gold and boots.
Remember : Last hit, Keep an eye on the minimap for junglers, call SS for missing champs and jungles. Target Ad carries, AP casters, and supports. Ward your lane.
Jungler
This role is really difficult and you need some time to learn it properly. Best champs to learn are Trundle, Evelynn (after patch) and nocturne. Jungler´s objective is farming from your and enemy jungle and winning ally lanes. The secondary objective is scoring kills in the process.
Why secondary ? – Believe it or not but killing the enemy is not your priority. Harrasing is. By killing you get gold etc.. But better is leaving kills for laners to help them in the lanes and force enemy champions to recall and waste precious creeps. If you must towerdive and you are certain he kills you DON'T DO IT. He steals your bonuses and your future jungle will be harder and you will be at a disadvantage against enemy junglers. With low level games don't bother about kills, scoring kills is also good :D and don't leave kill to your ally if there is even a slight possibility he can escape. (Flash, Ezreal´s teleport etc..)
When you jungle, you should be 5 – 10 creeps behind your mid and ad carry, and you should have lots of kills or assists. This way you know if you are good jungle.
When you jungle you want to start with blue (if your jungle uses mana) otherwise leave blue to mid, or start with red. Then you want to fast gank top (if the enemy is pushing lane) otherwise keep jungling. Go on wolves, then on wraiths, then on red. When your jungle is more or less empty go gank. You want to gank pushed lane from the enemy side. Signall your allies and jump on the most squishy OR the less mobile champ. On this lvl enemy tanks are not so tanky. You want to avoid enemy CC champions. Your main objective for your first gank is to harass the enemy. (waste his spell, mana, HP. In other words force him to recall or leave his lane.)
Then you want to either recall and buy items, or return to your jungle. Another duty of the jungler is to take over your allied lane, if your buddy is hurt, or forced to recall.
Note If you are on lanes and farm from creeps LAST HIT. You don't want to push your buddy´s lane. If you're in the jungle you want to learn how to last hit with smite. Training for Baron Nashor steal, Dragon and you take less dmg overall.
Why I need to guard the lane, the turret is strong enough to withstand enemy attack ?
But they take your turret s precious HP´s away and champions like Fiora with her Burst of speed ability can even kill it on the first push. Well with little help.
Important things to remember is to ward as a jungler. Jungler is warding by Wriggle´s lantern. One free ward every 180 secs. Ward high value targets like Dragon, later on Baron, or enemy jungle. Or as a last resort ward your ally´s lane if he refuses to ward.
Finally one of his last duty´s is to steal. Yes you want to steal valuable buffs while the enemy is working on them. That's why you last hit with smite. If you just smite the mob right away he will be having more than 75% HP´s and you will be vulnerable to enemy smite steal. You want to have your smite ready in late game, because of dragons :D and baron. If the enemy is working on baron and he doesn´t have smite, it's nothing better than flash + smite steal. Even if it costs you a life. You want to deny that buff.
An example of early game : One of my first champs was Eve, yes before the update she sucked hard. She was squishy, weak, she had one of the worst early game in every aspect, and she has been basically just movable ward in late game. But I think that makes my accomplishments much more impressive :D. Don't worry after the update she is superior jungle.
I start with 9/12/9 masteries. And with cloth armor and rest health potions. I start with blue and glance on the minimap if enemy top is pushing the lane. If not I go jungle as usual wolves, wraiths. If my smite is on more than 20 Sec away I go gank lines where my allies are in trouble, or where the enemy is just pushing the lane. I get the red buff and after another gank I check enemy blue or red buff. (To reset my timer on minimap, when he appears, He appears on my minimap too and I can easily steal him)
Note : If you are not so skilled don't steal the enemy buff unless you don't see him on minimap in another lane. (BECAUSE he can easily ambush you and steal your buffs).
When I reach near the 9-10 lvl ward dragon. (If I´m champing like fiddlesticks, when the lantern is not needed, I buy the damn ward.)
Remember : Jungle the jungle, gank often, ward dragon, baron, buffs. Last hit, Target AD carries, or AP casters.

AD carry.
One of the best roles for low skilled players. Because you start with a buddy on your lane. Your role is to farm and farm and farm. Of course using only LAST HITS. You want to play safe, last hit and not to push lane. If you are pushing lane, your support must ward. If enemy support is hiding in the enemy bush, your support should ward it. Try to deny enemy creep by lanning near him. Or hiding in enemy bush even though his creeps are pushing the lane. But be careful. Bot lane is after pushed top lane, the best place to gank.
Why ? Because you are usually 2 super squishy characters. And if you are pushing the lane, enemy jungle almost always has a guaranteed kill.
Your main role as ad carry is to carry the entire team. I know it sounds like a big responsibility (IT IS). You want to keep the damage on enemy all the time. When your jungle or tank tower dives enemy, keep the damage on him. (Auto attack, or spam the ability all the time) But remember AD carry´s are usually glass cannons. Enemy Junglers, tanks, supports and AP caster will be focusing you. Your job in team fights is to get rid of enemy AP casters and ad carries.
You as the main damage dealer want to have the Red buff on you as soon as possible. Leave the rest 2 to jungler then ask him for red. This will give you a little bit more damage.
For your summoner spell you don't want to ignite. You want to snipe enemy from a distance and casting ignite is difficult when you are in the back. Take heal instead.
But isn´t healing support´s duty ? Not necessarily, good supports will be usually taking flash and Clayrvoiance.
Example of early game : One of my favorite ad carries is ez and ashe. I will be playing as Ezreal. I start with 21/0/9 masteries and my first item I take Meki pendant for mana regen. I will be buying manamune later on. And some healing potions. I will be starting by guarding the red buff against the enemy team if need be. When minions start I return to the lane and start to form. I last hit only, and I try to deny enemy creeps by firing long range spells to keep him from last hitting. When we reached about middle of the lane support is going to ward the bush. I go with him in case enemy jungle will be waiting in the bush. I am keeping eye on enemy players. When I spot they are quickly closing by when our support is near the bush I quickly ping to retreat because this is clearly a sign of trap. My buddy has a fast reflexes and he quickly changes the direction. But enemy jungle jumps on him anyway. He flashed away and I teleported away too. Somehow they manage to kill my support, but I kill their jungle in the process. Then they kill me. I ping our jungle to take over my lane for when I respawn. I buy Tear of the goddess ans some health potions.
Note : Usually you want your second item you buy to be BF Sword. If you dont have on you the money try not to spend your money on Dorans. It can hurt you later in the game, but don't be stupid on not buy them when you clearly need damage.


Remember, stay back, keep the damage up, don't let them catch you off position or off guard. Even the enemy tank usually can kill you, Last hit
Support
Being a support is easy, being a great support is hard. Similar to Jungler, support needs some time to learn. Remember what character are you playing is secondary to what should you be doing in the game. Your duty as a support is to babysit AD carry early in the game, and warding, warding, warding. Good support has usually taken clairvoyance and flash. Let heal to your ad carry. If you are a low skilled player, I want you to remember one thing. WARD. Warding is a great thing, if not an only thing that gives your team a map awareness. Here is some link I want you to look into. http://i.imgur.com/9ETJ2.jpg - BTW great job to Basedtoney or anybody who came up with this great picture
Now remember when you are pushing a lane Ward top bush of the bottom lane. If your enemy is hiding in bushes, ward it. Every game try to start with Faerie charm + vision ward + 2 sight wards. This will give you a tool to detect enemy stealth champs, or rid of enemy wards in order to establish clear line for your jungle to gank.
As a support you want to either buff your AD carry, Harras enemy AD carry, Shield your AD carry, or heal your AD carry, by abilities ofc.
As a supporter you are forbidden to attack enemy creeps. You don't want to farm, you want to leave every single creep to your AD carry.
WHY ? I need money for my wards, and my items, ad carry will not be missing 10 creeps.
Yes he will. You want to have your income from assists and from money /10 sec based items. This way you can get more money then some not so skilled team mates. However you are allowed to last hit creeps when you AD carry is at spawn, or when you know he don't manage to kill the creep in time.
Buy oracle. Believe or not but detecting enemy champs is secondary. Your main objectives are wards, once you buy oracle, usually after the hearth of gold, or boots. Then go scout after enemy wards. (Dragon, Baron, Bushes).
Note : Oracles are expensive, DON'T DIE
If you are dying a lot, ask the tank to or jungle to buy it.
Supprt´s secondary role is actively to participated and separated or otherwise help your team in fights. (Shield as Janna against Zileans bomb, Stun as Sona etc..) As a support you want to be always in team fights, because of your buffs, you or your item is emmiting. And because you grant vision. Yes your ward, you clairvoyance bushes. Otherwise you try to clear the way. You make sure your team is not hiding in bushes, you make sure there are no teemo´s shroom in bushes. If they ambush you in team fight´s it is YOUR FAULT
Well again there is that dumb jungle :D
Example of early game : My favorite support is Janna, hoewer if you are learning you want soraka. Zilean is for the skilled :D. I start with 0/9/21 masteries and buy classic support items „go back“ I go and make sure they dont wait in any bushes on the bot lane. I have my finger on Flash if something will go wrong.
I don't go check out the bushes, if they have champs like Blitzcrank, or Alistart. (Hard CC champs)
I wait until minions spawn and making sure they don't ambushes us. I let my AD carry to farm and occasionally Troll him on the chat for not LAST HITTING :D After he calls me idiot. I ward top bush on the bot :D because our lane is slowly being pushed. Because his ad carry and support is starting to be agressive and they are hiding in our bush I ward it and clayrvoiance theyr jungle in the hope I catch they jungler on the way to the bot. I didn´t but this gave me the information no gank will be happening. On level 6 our lane is not being pushed so much. I with my AD carry starts to harass them, after some damage to them, they are trying to get away. But I flashed over him and activated my ulty and I Separated their ad carry and support. I then slow ad carry with W and scoring the kill. After that we are pushing a lane a bit and doing some damage to the turret. I recall home buying philosopher, ward, and boots.

Remember : Ward, Harras, heal, use your clairvoyance. DON'T FORGET BUYING WARDS !!. If you need creeps then LAST HIT.

In the end I want to give some useful tips.
1 kills = 10-15 creeps
1 assists = 4-7
Jungler is usually Assasin, or tank (off tank)
Ad carry doesn´t mean Tryndamere :D
Your buddy ulty is displayed on the portrait of your allies champ. The green dot if ulty is ready.
Learn to recognize Stun, Snares, Imobilize etc... Lux cannot stun AD carry etc.. It can save your life.
Learn to smart cast. Default Shift + QWER. It improves your performance by 200% literally.
Do not troll in chat. It only makes you look bad, instead try to appreciate how you were beautifully killed by enemy camp.
Check out WOWcrendor on YouTube. He makes some perfect videos on Lol. You can usually learn something from him.
Check out Mobafire builds. Important !!
Special thanks to Rifty, Kallis, Ariel, Kitty, Sonakra, AnalFor*****GAL SIGH – sorry